海蜇养殖对池塘底泥营养盐和大型底栖动物群落结构的影响

2009年5-9月,对荣成靖海湾大型养殖池塘海蜇(Rhopilema esculentum Kishinouye)养殖期间与养殖期前后底泥营养盐及大型底栖动物群落结构变化进行了研究。结果表明,7月份海蜇养殖期间,由于海蜇的避光性而产生的上下浮动的行为特征造成了对水体的扰动作用, 与海蜇的生物沉积作用共同导致养殖海区(实验点)与邻近非养殖海区(对照点)之间各项底泥营养盐指标均存在显著性差异,其中,实验点氨氮(NH₄-N)、硝氮(NO₃-N)和沉降速率(sedimentation rate, SR)显著高于对照点,实验点叶绿素a(Chla)、总有机物(TOM)和总有机碳(TOC)含量显著低于对照点。多变量聚类分析结果表明,海蜇养殖对养殖池塘的大型底栖动物群落结构产生显著影响,并且7月份实验点大型底栖动物生物多样性指数(H')和均匀度指数(J) 随海蜇放养显著增大,并显著高于对照点。大型底栖动物群落多样性指数与沉降速率(SR)和底泥TOM含量分别表现出显著正相关和负相关,而与其他营养盐指标无显著相关性。     

Effects of organic enrichment on meiofaunal abundance and community structure in sublittoral soft sediments

In experimental mesocosms established at Solbergstrand, Oslofjord, Norway, organic enrichment was effected by the addition of powdered Ascophyllum nodosum (L.) Le Jol., in quantities equivalent to 50gC·m^?2 and 200gC·m^?2, to boxes of sublittoral soft sediment. After 56 days, the structure of the meiofaunal communities in these treatments was compared with that of the control boxes. At this time the meiofaunal communites at each level of organic enrichment were markedly different from each other and from that in the control sediment. The responses of the two major components of the meiofauna, however, were different. Although the abundance of nematodes was slightly reduced in the high dose treatment this was not accompanied by detectable changes in community structure. Harpacticoid copepods, on the other hand, increased significantly in abundance in the treatment boxes and showed a general trend towards increased dominance and decreased diversity with increasing levels of organic enrichment, although in the low dose treatment there was also an increase in the number of species present. It is also shown that the nematode/copepod ratio is unreliable as a biomonitoring tool and it is suggested that the differential responses in community structure between the nematode and copepod components of the meiofauna might be a better indication of stress at the community level.     

Stratigraphic record of U37K in Sanmen Bay: the effect of SST and EI Niño on life activity in macrobenthos communities

Sea surface temperature (SST) from 1916–2003 was estimated by using the index of U₃₇^K of organic compounds in Sanmen Bay (SMB) sediment. It fluctuated between 15.97°C and 18.00°C with an average of 17.03°C. The estimated SST was 3.52°C lower than the annual average temperature measured in the same year but was close to the temperature measured in fall. The research suggested that the climate events (EI Ni?o) on large scale in Sanmen Bay were affected by the climate, similar to that in the East Pacific Ocean (EPC). The change scale was also affected by geographical location and local climate such as monsoon. According to the chronological basis, the events in SMB corresponded to those in EPC, but the scale of variation is not so strong as that in EPC. By comparing the community, biomass, individual density and biodiversity of macrobenthos during EI Ni?o (between 2002 and 2003) and non-EI Ni?o (between 2005 and 2006) periods, it was indicated that certain macrobenthos communities in SMB responded to EI Ni?o events. During the EI Ni?o period, Taiwan warm current (TWC) is much stronger than that in normal years. The diversity of macrobenthos during 2002 and 2003 was relatively low owing to invasion of the warm current that caused salinity change. The macrobenthos and zooplankton in Sanmen Bay responded to EI Ni?o events significantly. The diversity of macrobenthos decreased significantly because TWC invaded into the shallow bay from the floor and thus changed the temperature and salinity in the bay. On the other hand, zooplankton species, biomass and abundance increased in the period of EI Ni?o since the invaded warm current brought abundant species of zooplankton.     

UK37沉积地层记录:三门湾海表温度(SST)和EI Ni(n)o现象及其对大型底栖动物生命活动的影响

应用U^K37估算三门湾（1916～2003年）表层海水温度,SST波动范围在15．97～18．00℃之间,年平均为17．03℃,此计算值比当年实测海水全年平均温度低3．52℃,与秋季海水实测温度相接近。研究显示出,三门湾的EINino事件在大尺度上与东太平洋一样,均受制于气候影响因素,但在变化尺度上又受到地理位置和地方性气候（季风）的影响,事件在形式和年代上相互对应,但其颤动幅度远不如东太平洋强烈。同时通过比较EINino期间（2003／2002）和非EINino期间（2006／2005）大型底栖生物的群落结构变动信号、生物量、栖息密度以及物种多样性等,研究显示出三门湾若干大型底栖生物对EINino事件产生响应迹象,若干大型底栖生物对EINino的响应主要是通过海洋环流的影响来体现生命和生态效应的,主要表现在改变了底栖生物种类数和多样性、以及生命活动及栖息密度分布模式。在EINino影响下,台湾暖流人侵势力加强,2003／2002年底栖生物群落种类数减少与海流人侵及盐度密切相关;通过与同海域浮游动物对比研究,三门湾海域浮游动物和底栖生物对EINino的生态响应均较大,前者可能与三门湾海域水域较浅,外海暖水从底部人侵改变水温和盐度,直接影响底栖生物的生态环境,致使种类数大大减少有关;而后者由于人侵暖水强度增大,携带大量暖水性浮游动物,呈现出在EINino时期浮游动物种类数、生物量和丰度有偏高趋势。     

黄海特定断面夏秋季大型底栖动物生态学特征

根据2001年8月和2002年8、9、10月共4个航次,在黄海特定断面的10个站采集到的大型底栖动物样品,采用相对重要性指数、物种多样性指数、物种均匀度指数、物种丰度指数,Bray-Curtis相似性系数聚类分析和MDS标序等方法,分析了该区域大型底栖动物的生态学特性。调查共得到定量样品36个,经分析鉴定有大型底栖动物182种,其中多毛类环节动物54种,软体动物29种,甲壳动物66种,棘皮动物17种,其它类群生物16种。相对于邻近海区,物种丰富度指数较小,物种多样性指数相似,均匀度指数较高;各航次中4、5号站种数明显较少,而生物量和栖息密度没有表现出一定的规律性。通过该断面大型底栖动物的研究发现,可将研究区域的大型底栖动物群落分为沿岸广温性群落、温带性群落和暖水性群落,各群落结构保持相对稳定性;主要底栖动物种类组成在2001年和2002年出现较大变化,而在2002年的8、9、10月的种类组成保持相对稳定。     

Macrobenthos functional groups as indicators of ecological restoration in the northern part of China’s Yellow River Delta Wetlands

Freshwater releases to restore degraded wetlands are a globally recognized way to maintain the biodiversity and enhance the health of wetland ecosystems. To better understand the efficacy of freshwater releases in the northern part of China’s Yellow River Delta Wetlands, we used macrobenthos functional groups in spring (before freshwater releases), summer (during), and autumn (after) as indicators of the ecological responses. We also created abundance–biomass comparison curves and analyzed secondary production of each trophic level to evaluate the magnitude of the disturbance of the macrobenthos community. Abundance, biomass, and biodiversity of macrobenthos functional groups generally improved after the freshwater releases. In contrast with an intertidal (reference) area, the macrobenthos community in the ecological restoration area tended to be freshwater species. In the ecological restoration area, strong and moderate ecological disturbance of the macrobenthos community was evident during and after freshwater releases because the abundance curve remained above the biomass curve. Secondary production was in the order trophic level III > II ≅ IV in the summer, which indicates fragility of the macrobenthos community. The ecological restoration area had the highest sediment total organic carbon and moisture contents, but the lowest salinity and median particle size, and these differences were statistically significant. Our results suggest that adaptive freshwater releases, including a long-term freshwater release plan that more closely emulates natural flows and increasing the efficiency of freshwater utilization, will be necessary to achieve sustainable management of the wetland’s ecosystem and reduce the disturbance caused by the freshwater releases.     

The biodiversity of macrobenthos from Jiaozhou Bay

The current situation of the animal species biodiversity of macrobenthic fauna in the Jiaozhou Bay (South Shandong Peninsula, Yellow Sea) is reported in the present paper, based on the data from 15 investigation cruises carried out from February 1998 to November 2001. In analyzing the data, the Shannon-Wiener index, and species evenness and richness indices were used to study the trends of variation of the community structure, the species assemblages in the macrobenthic community, the dominant species, and the abundance of macrobenthic fauna in Jiaozhou Bay. A total of 322 species of macrobenthic animals were found in the bay, of which 133 species belong to 44 families of Polychaeta, while 92 species belong to 42 families of Crustacea. The average number of species per sample station ranged from 8 to 26. The Shannon-Wiener indices were very different among the samples, with the highest being recorded from Station 8 in November 2001, and the lowest from Station 9 in August 2001. The number of species, the Shannon-Wiener indices, and the species richness indices from Stations 7 and 9 were generally lower than those from other stations. This is because both the stations are situated at areas with a strong current and where the sediment is coarse sand. Although the richness index of species and the Shannon-Wiener index were high in Station 3, the Pielou evenness index was the lowest of all the sampling stations. This is because the station is located near the culture area of Ruditapes philippinarum, where a high abundance of clams caused low evenness. The results also revealed that the number of species and abundance greatly affected the biodiversity, and some environmental factors such as temperature, salinity, and primary productivity were also closely interrelated with biodiversity. Pollution and overexploitation caused by human activities were very important factors affecting macrobenthic biodiversity. In order to find the best way to enhance and protect living marine resources, the relationship between human activities and the biodiversity of macrobenthos in the Jiaozhou Bay should be studied further.     

The biodiversity of macrobenthos from Jiaozhou Bay

The current situation of the animal species biodiversity of macrobenthic fauna in the Jiaozhou Bay (South Shandong Peninsula, Yellow Sea) is reported in the present paper, based on the data from 15 investigation cruises carried out from February 1998 to November 2001. In analyzing the data, the Shannon-Wiener index, and species evenness and richness indices were used to study the trends of variation of the community structure, the species assemblages in the macrobenthic community, the dominant species, and the abundance of macrobenthic fauna in Jiaozhou Bay. A total of 322 species of macrobenthic animals were found in the bay, of which 133 species belong to 44 families of Polychaeta, while 92 species belong to 42 families of Crustacea. The average number of species per sample station ranged from 8 to 26. The Shannon-Wiener indices were very different among the samples, with the highest being recorded from Station 8 in November 2001, and the lowest from Station 9 in August 2001. The number of species, the Shannon-Wiener indices, and the species richness indices from Stations 7 and 9 were generally lower than those from other stations. This is because both the stations are situated at areas with a strong current and where the sediment is coarse sand. Although the richness index of species and the Shannon-Wiener index were high in Station 3, the Pielou evenness index was the lowest of all the sampling stations. This is because the station is located near the culture area of Ruditapes philippinarum, where a high abundance of clams caused low evenness. The results also revealed that the number of species and abundance greatly affected the biodiversity, and some environmental factors such as temperature, salinity, and primary productivity were also closely interrelated with biodiversity. Pollution and overexploitation caused by human activities were very important factors affecting macrobenthic biodiversity. In order to find the best way to enhance and protect living marine resources, the relationship between human activities and the biodiversity of macrobenthos in the Jiaozhou Bay should be studied further.     

Estuarine nematodes as indicators of organic pollution; An example from the Ems estuary (The Netherlands)

A comparison is made of the structure and abundance of the nematode community of an intertidal, brackish-water mudflat in the Ems estuary under conditions of high (1980) and reduced (1987) organic waste input. Three stations, at different distances from the waste water inlet, were sampled monthly; nematodes were identified and counted in the upper 1 cm of the sediment. In 1987, numerical density of nematodes was lower, and species diversity was higher than in 1980. Diatom eating nematode species dominated in 1980, to decrease by 1987.Eudiplogaster pararmatus, an indicator of organic enrichment, also decreased strongly. The response of the nematode community to reduced organic waste input could be adequately described with the BONGERS' Maturity Index.     

Species-abundance-biomass responses by estuarine macrobenthos to sediment chemical contamination

Macrobenthic community responses can be measured through concerted changes in univariate metrics,including species richness, total abundance, and totalbiomass. The classic model of pollution effects onmarine macrobenthic communities recognizes thatspecies/abundance/biomass (SAB) curves varydistinctively in a nonlinear manner with the magnitudeof organic enrichment. For example, at moderatelevels of organic enrichment, small-bodiedopportunistic species boost the abundance curve, whilespecies richness falls. Ratios among the metrics formuseful indicators of how the community changes withorganic enrichment. However, the classic SAB model isbased on organic enrichment effects over small spatialand temporal scales, and the applicability of the SABmodel to sediment chemical contamination and acrossbroad natural estuarine gradients is largely unknown. Here, SAB responses were examined with respect toprimary gradients in metals and organic chemicalsbased on an extensive dataset comprising 319 estuarinesites from throughout the northern Gulf of Mexico. Each SAB metric was first adjusted with respect to thethree primary natural estuarine gradients, salinity,depth, and sediment silt/clay content. Adjusted SABrelationships varied in their details with respect todifferent classes of sediment contamination, but alltypes of SAB stress responses appear to exhibitsimilar basic characteristics. As in the SAB model,all three SAB metrics were notably low at the highestconcentrations of both metal and organic-chemicalcontaminants. Moreover, rapid decreases in the B/Aratio with increasing contamination supported theconcept that relatively long-lived, large-bodied,equilibrium taxa decline markedly at highconcentrations of toxicants.     

The Influence of Dry-season Conditions on the Bottom Dwelling Fauna of an East Australian Sub-tropical Estuary

Spatial patterns in benthic infaunal community structure of Port Curtis estuary (north-eastern Australia) were determined from quantitative grab samples and examined in relation to environmental variables. A total of 149 riverine, estuarine and open coastal stations were sampled during the winter survey, and 5744 individuals from 466 species identified. Filter-feeding organisms (primarily polychaetes, molluscs and crustaceans) dominated the benthos, and accounted for 50% of the total species abundance and 30% of the total species richness. Most taxa were uncommon, and 98% of species individually represented less than 2% of the total abundance. Distributional patterns in total species richness and abundance were highly correlated, and both parameters varied significantly with sediment grain size. Numbers of species and individuals were typically highest in coarse-sand and gravel sediments, and were lowest in fine, well-sorted, sands. Cluster analysis of species abundance data revealed nine community groupings characterised by small species sub-sets with restricted distributions. These groupings were primarily related to sediment grain size, sediment organic carbon content, salinity and depth. Not all variation in community structure was explained by these environmental variables, and it is likely that other unmeasured factors play an important role in determining benthic faunal composition in the estuary.     

Impacts of an alien species (Spartina alterniflora) on the macrobenthos community of Jiangsu coastal inter-tidal ecosystem

Spartina alterniflora, a species vegetating on inter-tidal flats that was introduced from the eastern coast of United States, has become a hot topic, focusing on its invasion within local species in the coastal zone of China. Impacts of S. alterniflora on the inter-tidal macrobenthos community in the Jiangsu coastland are addressed by comparing the macrobenthos characteristics in a mudflat and in a four-year-old Spartina salt marsh that had earlier been a mudflat. During the period October 2002–July 2003, we studied the distribution pattern and diversity of macrobenthos, and discussed their correlation with environmental factors caused by Spartina vegetation. The results showed that a total of 43 macrobenthos species were found, mainly consisting of Mollusca, Crustacea, and Annelida. Ten macrobenthos species were found in the Spartina salt marsh, and 36 species were found in the mudflat. Life forms and functional groups of macrobenthos in the Spartina salt marsh were obviously distrinct from that of the mudflat. The study showed that macrobenthos diversity in the Spartina salt marsh decreased, and the community structure altered obviously, whereas the biomass showed no differences in different seasons. Statistical analysis demonstrated that seasonal change of macrobenthos diversity in the Spartina salt marsh negatively related to content of sediment organic matter, total N, bulk density, height and biomass of Spartina vegetation, and positively related to the density of Spartina. All these differences suggested the obvious effects of the Spartina vegetation on the Jiangsu inter-tidal benthic macroinvertebrate ecology. Furthermore, the investigation also showed that the niche of the native macrobenthos living in the mudflat has been transferred down, seaward, due to the invasion of Spartina in our study site.     

Diversity and composition of macrobenthic community associated with sandy shoals of the Louisiana continental shelf

Along the Louisiana, USA continental shelf, sandy shoals are shallow, possibly oxygen-rich “islands” surrounded by deeper muddy deposits prone to hypoxia. Shoals also contain significant quantities of fine sand that may be mined in the future for coastal restoration. The ecological role of shoals remains poorly understood and we hypothesized that shoals provide critical habitat for benthic invertebrates. Using Ship Shoal as a model system, we assessed the diversity and structure of macrobenthic assemblages and how community structure varies with season and environmental parameters. High biomass (averaging 26.7 g m⁻²) and high diversity (161 species) of macrobenthos was found in 2006. Polychaetes (45%—72 species) and crustaceans comprised most of the species (28%—46 species); spionids and amphipods dominated the polychaete and crustacean groups respectively, both in terms of number of species and abundances. Sharp decreases in diversity, abundance and biomass occurred from spring to autumn. Species diversity and total abundance significantly increased with decreasing sediment grain size and increasing bottom water dissolved oxygen. Across seasons, mole crabs Albunea paretii and amphioxus Branchiostoma floridae typified the community and contributed most of the biomass. The polychaetes Nephtys simoni, Neanthes micromma, Dispio uncinata, Mediomastus californiensis and Magelona sp. A, the amphipod Acanthohautorius sp. A and the burrowing shrimp Ogyrides alphaerostris also contributed to variation in community composition. Cluster analyses quantified seasonal variation, mainly based on sharp decreases in abundance, as well as spatial differences in species composition oriented along both east–west and north–south gradients. Variation in benthic assemblages was correlated with water depth and sediment characteristics (mean grain size and percentage of gravel-sized shell debris). We conclude that Ship Shoal is an unrecognized biodiversity hotspot and a hypoxia refuge compared to the immediate surrounding area where the benthic community is affected by seasonal hypoxia events and we discuss how sand-mining may influence this community.     

Benthic fauna bio-irrigation effects on nutrient regeneration in fish farm sediments

Impacts of organic enrichment and a modified benthic fauna community (caused by fish farming) on benthic mineralization rates and nutrient cycling were studied in sediments at one Danish and one Cypriote fish farm. Sediment organic matter concentration and macrofauna community composition were manipulated in microcosms and changes in total benthic metabolism (oxygen consumption, TCO₂ production), anaerobic metabolism (sulfate reduction rates), nutrient fluxes and sediment parameters were followed for a period of 3 weeks. Mineralization rates were found to be highly correlated with irrigation velocities and largest fauna effects were found in the Danish sediments with the large and active irrigating climax species (Nereis diversicolor and Macoma balthica). Eastern Mediterranean climax species (Glycera rouxii and Naineris laevigata) also stimulated mineralization rates but to a smaller extent due to lower irrigation, whereas the opportunistic species (Capitella in Danish sediment and Hermodice carunculata in Cypriote sediment) showed less effect on mineralization. Ammonium and phosphate release increased with increasing irrigation velocities, but much less in Cyprus indicating higher nutrient retention at the ultra-oligotrophic location compared to eutrophic Danish site. Irrigation velocities, and thus mineralization rates, increased by organic matter loading, indicating larger fauna-induced oxidation in enriched environments. The result implies that a change in fauna structure in fish farm sediment towards smaller opportunistic polychaete species with lower irrigation will result in slower mineralization rates and potentially increase accumulation of organic waste products.     

莱州湾大型砂壳纤毛虫群落季节变化

为揭示莱州湾砂壳纤毛虫群落季节变化规律, 在莱州湾设置8个站位, 于2011年5-11月及2012年3-4月进行了9个航次的调查, 用浅海III型浮游生物网由底至表垂直拖网采集砂壳纤毛虫。结果表明, 莱州湾3-11月砂壳纤毛虫物种丰富度的变化范围为5-19, 周年变化呈现一峰两谷的趋势。丰度的范围为0-318 ind./L, 丰度较大(> 50 ind./L)的种类有运动类铃虫(Codonellopsis mobilis)和清兰拟铃虫(Tintinnopsis chinglanensis)。各月平均丰度随时间的变化趋势为双峰型, 最大值出现在7月(63 ind./L), 次峰值出现在5月(48 ind./L), 最小值出现在3月(2 ind./L)。黏着壳种类在3-11月均有出现, 透明壳种类仅在温度较高(> 15°C)的6-9月出现。各月的优势种数目为1种(5月)到8种(8月), 其中运动类铃虫在所有月中都是优势种, 对砂壳纤毛虫丰度周年的变化规律产生较大影响。使用各月所有种类的平均丰度对各月砂壳纤毛虫群落进行聚类分析, 得到两个群落(相似度30%): 群落I(7-9月)和群落II(3-6月、10-11月), 说明砂壳纤毛虫群落发生了明显的季节变化。砂壳纤毛虫的物种丰富度、丰度与环境因子(温度、盐度)均没有明显的相关性。     

Importance of predation by white shrimp Litopenaeus setiferus on estuarine subtidal macrobenthos

Macrobenthic invertebrates are an important food source for higher trophic levels in freshwater and marine habitats, yet the importance of predation impacting regular seasonal changes in macrobenthos abundance remains unclear. Benthic invertebrates and transient marine species in temperate estuaries display inverse patterns of seasonal abundance, suggesting a link between predation and summer macrobenthos abundance minima. We conducted manipulative caging experiments to test the importance of predation by white shrimp (Litopenaeus setiferus) in regulating estuarine subtidal macrobenthos densities. We predicted greater declines in macrobenthos densities with increased shrimp densities due to predation rather than disturbance and macrobenthos emigration. Using these field and laboratory data, we estimate whether white shrimp predation can significantly contribute to the macrobenthos seasonal abundance minima observed in long-term monitoring data.White shrimp predation was measured in the field using 7-d predator enclosure/exclusion experiments. Within the uppermost 0-2 cm of sediment, total macrobenthos densities decreased within shrimp enclosure cages using 12 or 36 shrimp m^− 2. Laboratory experiments distinguished between the effects of shrimp predation versus shrimp disturbance and macrobenthos emigration. Shrimp predation significantly reduced macrobenthos densities, while effects of shrimp disturbance and macrobenthos emigration were not significant in these experiments. Despite the impacts from other ambient predators and other abiotic factors, white shrimp were clearly capable of driving subtidal macrobenthos from their annual maximum density in winter/spring to their summertime minimum density.     

Response of Benthic Foraminifera to Organic Matter Quantity and Quality and Bioavailable Concentrations of Metals in Aveiro Lagoon (Portugal)

This work analyses the distribution of living benthic foraminiferal assemblages of surface sediments in different intertidal areas of Ria de Aveiro (Portugal), a polihaline and anthropized coastal lagoon. The relationships among foraminiferal assemblages in association with environmental parameters (temperature, salinity, Eh and pH), grain size, the quantity and quality of organic matter (enrichment in carbohydrates, proteins and lipids), pollution caused by metals, and mineralogical data are studied in an attempt to identify indicators of adaptability to environmental stress. In particular, concentrations of selected metals in the surficial sediment are investigated to assess environmental pollution levels that are further synthetically parameterised by the Pollution Load Index (PLI). The PLI variations allowed the identification of five main polluted areas. Concentrations of metals were also analysed in three extracted phases to evaluate their possible mobility, bioavailability and toxicity in the surficial sediment. Polluted sediment in the form of both organic matter and metals can be found in the most confined zones. Whereas enrichment in organic matter and related biopolymers causes an increase in foraminifera density, pollution by metals leads to a decline in foraminiferal abundance and diversity in those zones. The first situation may be justified by the existence of opportunistic species (with high reproduction rate) that can live in low oxic conditions. The second is explained by the sensitivity of some species to pressure caused by metals. The quality of the organic matter found in these places and the option of a different food source should also explain the tolerance of several species to pollution caused by metals, despite their low reproductive rate in the most polluted areas. In this study, species that are sensitive and tolerant to organic matter and metal enrichment are identified, as is the differential sensitivity/tolerance of some species to metals enrichment.     

营养盐加富和鱼类添加对浮游植物群落演替和多样性的影响

浮游植物是水体生态系统敞水区最重要的初级生产者,其组成与多样性反映了群落的结构类型和存在状态。通过围隔实验,模拟水库春季发生的营养盐加富和鱼类放养的干扰,分析在这两种干扰下的浮游植物群落演替过程中优势种和稀有种的变化,并通过以丰度与生物量为变量的香农和辛普森多样性指数的计算,分析浮游植物群落演替过程中的多样性变化特征。结果表明,营养盐加富干扰下的浮游植物群落的优势种变化和演替更为明显,营养盐加富与鱼类添加对浮游植物群落多样性变化的影响符合中度干扰理论。在优势种优势度变化较大的浮游植物群落演替过程中,多样性指数与浮游植物生物量有较高的负相关性。在浮游植物群落演替过程中,香农和辛普森多样性指数的变化趋势基本一致,采用丰度与生物量为变量的两种多样性指数的计算结果对实验系统中浮游植物群落多样性的分析结果没有明显的影响。     

清潩河(许昌段)流域生物群落特征及其与环境因子的关系

以清潩河(许昌段)流域为研究对象,通过野外调查和室内测定,对水生植物、河岸带植物和大型底栖动物的群落特征、水体和表层沉积物的环境因子特征进行研究,分析清潩河流域内的生物多样性.结果表明: 流域内共有水生植物12种,河岸带植物66种,大型底栖动物10种.群落间环境因子变异较大,其中,水体的铵氮、总氮、总磷、表层沉积物的氧化还原电位、重金属镉、汞、锌的变异显著.典范对应分析表明: 水体理化性质如化学需氧量、温度、pH、溶解氧、总磷是影响水生植物的关键环境因子;水体氧化还原电位、pH和表层沉积物的镍、汞、有机质、铅、镉是影响河岸带植物分布的关键因子;表层沉积物的pH、温度、氧化还原电位、砷、铅、镍和水体温度是影响大型底栖动物的关键环境因子.清潩河(许昌段)流域水质污染严重,生物群落多样性低,沿河的污水处理及保护与恢复生物类群的工作迫在眉睫.